Aluminum ferrule-copper tongue terminal and method of making



p 1957 J. J. REDSLOB 2,806,215

ALUMINUM FERRULEI-COPPER TONGUE TERMINAL AND METHOD OF MAKING Filed Nov. 4. 1953 COPPER 0R BRASS A BRASS COPPER 01? BRA-3.5

(UPPER 0R BRASS INVE TOR, (Zs-w/v 0. 501108 ATTORN S.

United States Patent ALUMINUM FERRULE-COPPER TONGUE TERMINAL AND METHOD OF MAKING Jean J. Redslob, Harrisburg, Pa., assignor to Aircraft Marine Products, Inc., Harrisburg, Pa.

Application November 4, 1953, Serial No. 392,182

9 Claims. (Cl. 339-476) This invention relates to electrical terminals, particularly to the type to be secured by crimping to aluminum wire. The invention is described as embodied in a ter minal for aluminum wire and which is adapted to make connection with a copper conductor, such as a bolt or other terminal securing means.

It has been found most difficult to make electrical connections between aluminum wires and circuit elements of other metals such as copper. The more important factors in causing these difiiculties are the insulating oxide coating that forms on the aluminum, the battery action between the two dissimilar metals, corrosion, and the differential expansion rates for the different metals with changes in temperature.

The present invention provides a terminal connection in which these troubles are eliminated, or at least alleviated to a large degree. In a preferred embodiment of the invention, a copper or brass terminal means, such as a spade tongue, is provided with an upstanding annular ring which is welded around its periphery to a short length of aluminum tubing which serves as the barrel or ferrule of the terminal. This aluminum ferrule is crimped to the aluminum conductor.

By this construction, as will be described more fully later, the crimped connection is between two aluminum members, thus eliminating loosening of the connection because of differential expansion with changes in temperature, and minimizing battery action and corrosion.

These broad objectives and others more specific will be made more apparent by the following description considered in conjunction with the accompanying drawings, in which:

Figure l is a perspective view of the parts of a connector embodying the invention ready to be assembled to an insulated aluminum cable;

Figure 2 shows the connector of Figure 1 after being assembled with and crimped to the cable;

Figure 3 is a perspective view illustrating the first step in fabricating the terminal portion of the connector;

Figure 4 is a perspective view of the partially fabricated terminal portion;

Figure 5 is an elevational view of the completed terminal and ferrule portions of the connector ready to be welded together;

Figure 6 illustrates the first step in an alternative method of making the terminal portion;

Figure 7 shows a completed terminal portion fabricated from the metal shown in Figure 6; and

Figure 8 shows another form of connector which eliminates the need for a separate thimble insert.

As shown in Figure l, the connector includes a tubular ferrule or barrel portion 2 having a closed end as at 4 to which is secured an extending terminal tongue or eyelet 6.

The main portion of the ferrule 2 is formed of aluminum tubing, but the closed end 4 and an adjacent ring portion 8 are formed of copper, the ring and tubing being welded or soldered together along a peripheral line 10. The tongue 6, which may be any desired form of terminal connecting means, is formed integrally with the ring portion 8 and is also of copper.

In use, it is preferred to uSe a thin-Walled drawn aluminum thimble 12 with the terminal. This thimble, which advantageously is tin-plated, has a tubular insert portion 14, which is adapted to fit within the ferrule 2, and an enlarged insulation-support portion 16 which fits over the outside of. the insulation 18 of an aluminum wire cable 20.

The thimble 12 is partially filled with a corrosion-inhibiting jelly, such as petrolatum, silicone grease, or the like, in which are dispersed fine particles of an abrasive material such as nickel powder, alundum, zinc dust, etc. This composition is for the purpose of aiding in the removal of the oxide coating and later in retarding its reformation.

To assemble the connector the insulation is trimmed from the end portion of the cable 20 and the bared aluminum wire 22 is inserted into the insert portion 14 of the thimble 12, the wire extending almost to the closed end of the thimble 12. The insulation support 16 fits over the end portion of the insulation 18 which extends into the thimble the full depth of the insulation support. The insert portion 14 of the thimble is then inserted all the way into the ferrule 2 so that its closed end is adjacent one end of the ferrule and the junction of the thimble insert 14 and insulation support 16 is adjacent the other end.

The ferrule 2 is then crimped in a confining die to the wire 22 and the support 16 is crirnped tightly around the insulation 18. The assembled terminal after crimping is shown in Figure 2.

The quality of the resulting connection will depend upon the shape of the crimping dies, the extent of the extrusion produced by the crimping, the composition of the jelly and other factors which do not form part of the present invention but which are discussed more fully in my copending application Serial No. 350,653, filed April 23, 1953.

Preferably the outer surface of the ferrule is coated with a moisture-resistant coating to retard electrolytic corrosion at the outer surface of the junction between the aluminum and copper. Thus, the outer surface of the ferrule 2 may be painted, coated with plastic or otherwise treated to minimize the electrolytic action.

The tongue portion 6 and ring or cup portion 8 advantageously are formed from sheet copper. For example, a shallow depression or cup 24 (Figure 3) can be drawn in the copper sheet as shown in Figure 3. A blank 26 is then formed by cutting along the broken line 28 and punching out the hole 30 in the tongue. The blank 26 then appears as shown in Figure 4. The tongue portion 6 is then bent backwardly perpendicularly to the end surface 4 of the ring 8 so that it appears as shown in Figure 5.

The ring 8 is shown in Figure 5 in position to be buttwelded to the aluminum tubing which forms the ferrule 2. The welding can be performed in any desired manner; a synchronized flash and upsetting electric welding ope ration gives good results. Apparatus for making such welds between aluminum and copper is manufactured by Thompson Electric Welder Company, Lynn, Massachusetts. After the welding operation, the excess metal on the outside of the welding joint 10 is ground oil to produce a reasonably smooth surface. The ferrule 2 preferably is then painted or coated with other moisture resistant material.

As pointed out in the aboveidentified copending application, it is of advantage to plate the aluminum ferrule with tin. This tin plate may be applied before the welding operation, for example in accordance with the procedure set forth in said copending application, or the entire assembly after the ferrule 2 and tongue portion 6 are welded together can be plated with tin. Usually, however. it is the better practice to apply the tin plating after the connector is completely fabricated. If the tin plating is applied prior to the welding operation, part of it is re moved during the welding and the subsequent grinding operation which removes the flash. After the welding operation a moisture resistant outer coating is applied.

A preferred plating method is to treat only the alum inum portion of the fabricated terminal with the zincate solution (as described in the previously identified copending application) after which the entire connector, both copper and aluminum parts, is given a copper flash and then plated with tin.

Preferably the ring 8 is provided with the solid end portion 4 as shown in Figure l as this helps to seal the interior of the ferrule against moisture and retards electrolytic corrosion and oxide formation within the ferrule 2. However, where such corrosion or oxidation are not considered detrimental in the particular applica tion, the end portion 4 may be punched out or the ring portion 8 can be formed from a strip of copper which is shaped into an annular ring, the adjacent ends being brazed or otherwise secured together. The ring can then be welded to a separate tongue portion 6.

Another method of forming the ring 6 and tongue 8 is illustrated by Figure 6. A blank is cut, as indicated by the broken lines, from a sheet 34 of copper. The two strip-like arms 36 are then bent upwardly and around into the ring 8 as shown in Figure 7, and the ends are brazed or otherwise secured together as along the line 38.

When the end of the ring 8 is left open in the lastdescribed construction, it is particularly important to use the thimble 12 to insure that the pressure connection with the aluminum wire is protected from the atmosphere, the connection between the outer surface of the thimble 12 and the inner surface of the ferrule 2 being more resistant to corrosion and oxidation if both surfaces are plated with tin or other suitable metal.

It will be noted also that the present invention makes it convenient to use seamless aluminum tubing for the ferrule thus avoiding the necessity for a longitudinal weld or braze along the ferrule. This arrangement thus has advantage in the construction of an all-copper terminal in which a short length of seamless copper tubing is Welded to the ring 8 in the manner described above.

Figure 8 shows a construction by which it is possible to eliminate the thimble l2 and still provide a satisfactory seal for the connection. The tubular ferrule portion of this connector is aluminum and is formed by drawing to have a thick-walled portion 40, which is to be crirnped to the wire, and a thin-walled portion 42, which is to be crimped around the insulation.

The trick-walled portion of the ferrule is welded to a copper end plate 44, in the manner described above, the end plate may be formed from sheet copper by blank ing, coining an annular nib 46, and bending the tongue portion 48 as shown. The ferrule portion 40 is welded at 50 in end-toend position with the annular nib 46 and the excess metal is removed by grinding. The connector is then plated with tin as already described. No insert thimblc is required as the end plate 44 seals one end of the connection and the insulation-crimping portion 42 seals the other end. The use of corrosion-inhibiting jelly as described above is, of course, desirable.

From the foregoing, it will be seen that the improved connection embodying the present invention is well adapted to be manufactured by conventional techniques from readily obtainable materials and that it can be modified in various ways to meet the particular needs of each use.

What is claimed is:

l. A terminal for making connection between a copper conductor and an aluminum wire, said terminal comprising a copper tongue, copper ferrule-connecting por tion comprising a cup formed integrally with said tongue. said cup having walls and a closed end positioned in a ill plane substantially perpendicular to the plane of said tongue, and a tubular aluminum ferrule Welded in endtoend relationship to the walls of said cup.

2. A connector for making connection between an aluminum wire and a conductor of dissimilar metal, said connector comprising a tubular ferrule formed of metal composed predominantly of aluminum, and a tongue portion formed of metal composed predominantly of copper, said tongue portion including an extension connectiblc to said conductor and an upstanding ferrule-securing por tion including an annular ring portion having a diameter substantially equal to that of said ferrule, said collar and ferrule being welded together in end-to-end abutting re lationship.

3. A terminal for making connection between an aluminum wire and a conductor of dissimilar metal, said terminal comprising a contact portion including tongucdikc extension and an annular ferrule-connecting ring portion extending at an angle from and integrally connected to. said extension, said contact portion being formed of metal composed predominantly of copper, and a tubular forrule in end-to-end relationship with and welded to said ring portion, said ferrule being formed of metal composed predominantly of aluminum.

4. A connector for making connection between an aluminum wire and a releasable fastener of dissimilar metal comprising a tubular ferrule formed of metal composed predominantly of aluminum, and a tongue portion formed of metal composed predominantly of copper, said tongue portion including a substantially planar extension connectiblc to said releasable fastener and an upstanding ferrule-securing portion including an annular ring portion having a diameter substantially equal to that of said ferrule, said ring portion and ferrule being welded to gether in cnd-tc-end abutting relationship, the axial length of said ferrule being substantially greater than the length of said ring portion.

5. The method of making a terminal suitable for use in connecting an aluminum wire and a conductor of dissimilar metal, said method comprising forming from sheet metal composed predominantly of copper :1 blank in cluding a tongue portion integral with a ring portion, bending the ring portion into a position subst'i. 1 pendicular to said tongue portion, assembling a tubular ferrule of metal composed prcdominantly of aluminum into abutting relation with said ring portion, and welding; said ferrule and ring portion.

6. A terminal for making connection between a conductor and an aluminum wire, said terminal including a tongue portion formed of metal com-posed predominantly of copper and a ferrule-end portion extending at an angle from said tongue portion, said ferrule-end portion being of the same metal as said tongue portion and integral therewith, a tubular ferrule portion formed of metal. composed predominantly of aluminum, said ferrule portion being butt welded with said ferruloend portion, and a thimble formed of metal composed predoniimintly of aluminum, said thimble fitting within said ferrule portion and being adapted to receive the end of the wire.

7. A terminal for making connection between two condoctors of dissimilar metals, said terminal including a tongue portion formed from a sheet of a first metal, a fcrrule-end portion integral with said tongue portion and formed from said sheet, and a ferrule portion formed o tubing of another metal, butt welded with acid ferruleend portion, one of said meta s being composed predominantly of copper, the other of said metals being predominantly of aluminum.

8. A solderless type connector adapted to be crirnpcd to an insulated wire comprising a tubular ferrule portion, a tongue portion extending from one end of said ferrule, and a tubular insulation-supporting portion extending from the opposite end of said ferrule, said insulation-supporting portion being integral with said ferrule portion and having a wall thickness significantly less than axial that of said ferrule portion, the internal diameter of the insulation-supporting portion being larger than that of the ferrule portion, and said conector having an end plate formed integrally with said tongue portion and extending at an angle thereto, said end plate having a raised annular ring portion soldered to said ferrule portion.

9. A solderless type connector adapted to be erimped to an insulated wire comprising an aluminum tubular ferrule portion, a copper tongue portion extending from one end of said ferrule, and a tubular insulation-supporting portion extending from the opposite end of said ferrule, said insulation-supporting portion being integral with said ferrule portion and having a wall thickness significantly less than that of said ferrule portion, the internal diameter of the insulation-supporting portion being larger than that of the ferrule portion, and said connector having a copper end plate formed integrally with said tongue portion and extending at an angle thereto and said end plate having a raised annular ring portion welded to said ferrule.

References Cited in the file of this patent UNITED STATES PATENTS 

